Some drug compounds act by stimulating certain key aspects of the immune system, as well as by suppressing certain other aspects (e.g., U.S. Pat. Nos. 6,039,969 and 6,200,592). These compounds are sometimes referred to as immune response modifiers (IRMs). Some IRM compounds are useful for treating viral diseases, neoplasias, and TH2-mediated diseases; some are useful as vaccine adjuvants.
IRM compounds have been reported based on the following bicyclic and tricyclic ring systems: 1H-imidazo[4,5-c]quinolin-4-amines (e.g., U.S. Pat. No. 4,689,338); 1H-imidazo[4,5-c]pyridin-4-amines (e.g., U.S. Pat. No. 5,446,153); 1H-imidazo[4,5-c][1,5]naphthyridin-4-amines (e.g., U.S. Pat. No. 6,194,425); thiazolo[4,5-c]quinolone-4-amines and oxazolo[4,5-c]quinolone-4-amines (e.g., U.S. Pat. No. 6,110,929); 6,7,8,9-1H-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amines (e.g., U.S. Pat. No. 5,352,784); 2H-pyrazolo[3,4-c]quinolone-4-amines (e.g., U.S. Pat. No. 7,544,697); and N-1 and 2-substituted 1H-imidazo[4,5-c]quinolin-4-amines (e.g., U.S. Pat. Nos. 6,331,539, 6,451,810, 6,664,264, 8,691,837, 8,088,790, 8,673,932, 8,697,873, 7,915,281).